Silicone Sealant Base Polymer (α,ω-Dihydroxy Polydimethylsiloxane)
CAS Number: 70131-67-8
α,ω-Dihydroxy polydimethylsiloxane (PDMS) is the primary base polymer for room-temperature-vulcanizing (RTV) silicone sealants, offering a unique combination of flexibility, thermal stability (−60 °C to +200 °C), and UV resistance. It crosslinks with silane crosslinkers in the presence of moisture and tin or titanium catalysts to give durable, elastic seals. The polymer backbone is chemically inert, water-repellent, and resistant to ozone and UV degradation.
Technical Specifications
| viscosity | 20,000–100,000 mPa·s (25 °C, grade dependent) |
| volatiles | ≤1.0% |
| appearance | Colorless transparent viscous liquid |
| hydroxylContent | 0.03–0.10% |
| specificGravity | 0.97–0.98 |
Applications
- Construction weatherproofing and glazing sealants
- Automotive and aerospace sealing
- Electronics and electrical sealing compounds
- Sanitary (mold-resistant) sealants
- Industrial maintenance sealants
Key Features
- Exceptional temperature range (−60 °C to +200 °C)
- Outstanding UV and ozone resistance
- Inherently water-repellent and flexible
- Compatible with RTV-1 and RTV-2 sealant formulations
Send Inquiry
CAS Number
70131-67-8
Category
Adhesive / Sealant AdditivesAvailability
In StockSample
Dispatched within 5 days
More in Adhesive / Sealant Additives
Acrylic Pressure Sensitive Adhesive
9003-01-4
Anaerobic Adhesive Monomer
868-77-9
BDMA (Benzyldimethylamine) Epoxy Accelerator
103-83-3
Bisphenol F Epoxy Resin (DGEBF)
28064-14-4
Butyl Glycidyl Ether (BGE) Reactive Diluent
2426-08-6
C12–C14 Alkyl Glycidyl Ether Reactive Diluent
68609-97-2
C5 Aliphatic Hydrocarbon Tackifier Resin
68131-77-1
C9 Aromatic Hydrocarbon Tackifier Resin
64742-16-1